Center plate lubricating device



Dec. 22, 1970 w, WATSONv 3,549,217

CENTER PLATE LUBRICATING DEVICE Filed Nov. 29, 1968 u-- pn-apiip-nm----1''... 'IIDII'I.

, -q 2e 16 j Inventor William. R. Watson. 3 MmaaQ,W, Cavk & Enf- UnitedStates Patent 3,549,217 CENTER PLATE LUBRICATIN G DEVICE William R.Watson, Oak Lawn, Ill., assignor to Nalco Chemical Company, Chicago,11]., a corporation of Delaware Filed Nov. 29, 1968, Ser. No. 779,885Int. Cl. B61f 5/16 US. Cl. 308-137 5 Claims ABSTRACT OF THE DISCLOSURE Ahigh strength, non-dusting center plate lubricating device whichcomprises a paper disc adapted to fit between a body bolster centerplate and a truck bolster center plate. The paper disc is uniformlyimpregnated with -60% by weight of molybdenum disulfide.

INTRODUCTION The center plate assembly of a railroad car is part of thetruck wheel frame assembly. The center plate assembly consist of twocomponents. They are the body bolster center plate and the truck bolstercenter plate.

The truck bolster center plate is physically part of the truck wheelframe. More specifically, it is in the center of the frame member whichis parallel to the railroad car wheel.

The body bolster center plate is the removable portion of the centerplate assembly. It is adapted to fit on top of the truck bolster centerplate.

The center plate assembly has a circular center opening adapted to fit asolid cylindrical pin. The pin is dimensioned to be in loose fittingrelationship with the center openings of the center plate assembly.

Normally two trucks are used to carry one railroad car. The bottomsurface of the railroad car which rides parallel to the ground isdesigned with two circular openings centrally located near the ends ofthe car. These openings are adapted to fit the cylindrical pin of thecenter plate.

The function of the center plate is to allow the swiveling of the truckportion of the railroad car when traveling on curved tracks.

The swiveling motion is allowed by the pivoting action of the centerplate assembly. However, this pivoting action necessarily requires themovement of the surfaces of the body bolster plate and the truck bolsterplate against one another. As a consequence, the contacting surfaces ofthe respective center plate portions require lubrication.

Inadequate lubrication will result in severe 'galling and unduefrictional wear. Inadequate lubrication will also result in arestriction in the case of swiveling of the railroad car trucks. Such arestriction causes increased wheelflange wear, reduction of lateralthrust on journal bearings, increase in hot-boxes and probably mostimportant non-uniform train resistance. Many substances have beenapplied to center plates in the hope of finding an adequate lubricant tominimize these problems.

Many of the common petroleum based greases have been tested. However,such greases have failed to provide adequate lubrication, even for shortperiods of time. These greases completely disappear from the centerplate contact area after a short period of time. They are extruded overthe rim of the truck center plate.

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Solid compounded lubricants have also been tested. The solid compoundedlubricants appear to produce better results than the greases. However,the period of time for which they offer protection is relatively small.

Attempts have also been made to use graphite applied in a laquer carrierto a depth of 6" to the truck center plate. Experience with this type oflubrication system indicates that under extreme conditions oftemperature and pressure the lacquer oxidizes and resinifies, therebyproducing abrasive substance which counteracts the lubricity imparted bythe graphite.

Thin plastic discs impregnated with either molybdenum disulfide orgraphite afford lubrication to the center plate and prevent metalseizure. However, the discs themselves eventually disintegrate andportions are extruded over the rim of the center plate. The coatingsafforded by these devices were not uniform in all cases.

Certain liners were also tested and proven unsatisfactory. Examples ofsuch liner compositions are: High tensile bronze liners and phenoliclaminated fabric liners, soft steel liners, and 325 Brinell liners.Their ability to provide adequate lubrication was marginal. They alsocaused dangerous conditions since sharp edges were formed whichprotruded form the center plate pin.

From the above, it maybe concluded that many schemes have been testedand proposed in an effort to afford adequate long life lubrication tocenter plate assemblies. Grease-like substances tend to be extruded frombe tween the surfaces of the mating center plates, thereby deprivingcertain of the contact areas with a lubricant film. Greases and otherdevices or methods which have been used, while alfording short termlubrication, are not capable of impartinlg long term lubrication to thecenter plate assemblies. In other cases Where adequate lubrication isachieved, many of the devices are expensive and diflicult tomanufacture, there-by making their use economically prohibitive.

It would be a great benefit to this art if an inexpensive yet effectivedevice or lubricating system were available which could providelubrication to center plate assemblies lasting for long periods of timeat low cost. Such a device should be simple to manufacture and should becapable of installation or application without the need of specialequipment or trained personnel. Another desirable feature for alubricant or device would be a lubricant which possesses suchcharacteristics as high shear strength, is non-dusting and would nottend to be extruded under conditions of normal usage.

OBJECTS It is, therefore, an object of this invention to provide alubricating device specifically adaptable to lubricate center plateswhich exhibit the following properties: (1) providing long termlubrication, (2) high shear strength, and (3) non-dusting.

THE DRAWINGS For a more comprehensive understanding of the invention,reference may be had to the drawings of which:

FIG. 1 is a top view of the molybdenum disulfide impregnated paper disc.

FIG. 2 is a horizontal cross-sectional view taken across lines 22 ofFIG. 1.

FIG. 3 is a horizontal cross-sectional view of a typical center plateassembly, containing the molybdenum disulfide impregnated paper disc ofthe invention.

With specific reference to the drawings, there is shown in FIGS. 1 and 2a paper disc which contains uniformly distributed therethroughou-tmolybdenum disulfide particles 12.

FIG. 3 illustrates a typical center plate assembly 14 which is composedof a body bolster plate 16 and a truck bolster plate 18.

The truck bolster plate 18 is in the form of a dish having sidewalls 20and a flat bottom surface 22 which rnates with a corresponding face 24of the body bolster plate 16.

Both the body bolster plate 16 and the truck bolster plate 18 contain intheir center, mating hub assemblies 26 and 28 respectively which containtherein vertically positioned openings 30 and 31 which are adapted toreceive a pin 32 in loose fitting relationship.

Pin 32 is adapted to engage an opening 33 located in the bottom of atypical railway car, a portion of which is designated generally by thenumeral 34.

Positioned between flat bottom' surface 22 of truck bolster plate 18 andface 24 of body bolster plate 16 is the molybdenum disulfide paperimpregnated disc 10. The weight of the mating faces 22 and 24 inconjunction with the horizontal rotation imparted thereto by themovement of railway car body 34 tend to disintegrate paper disc 10 andimpart to matingfaces 22 and 24 a tenaciously bonded thin film ofmolybdenum disulfide. As will be shown later in the examples, the filmof the molybdenum disulfide is characterized as being uniformly coatedover the mating faces of the center plate assembly 14.

The relative dimensions of the center plate assemblies will vary withthe normal load capacity which is to be carried. Table I shows thetypical geometric dimensions of the center plate components as afunction of load capacity.

THE INVENTION The invention is directed to a device and method adaptedto provide long term lubrication for railway car center assemblies. Verysimply, the invention comprises a disc .ofpaper uniformly impregnatedwith. from 10 to 60% by weight and preferably 20 to 40% by weight offinely divided molybdenum disulfide.

The diameter of the paper disc depends upon the diameter of the centerplate assembly in which it is to be used. Generally center platediameters vary between 12 and 16 inches depending on the nominal carcapacities. As a consequence, the diameter of the paper disc of thisinvention will vary between 12 and 16 inches.

Typical thickness of the paper discs of this invention will vary from0.001 to 0.5 inch in thickness.

THE MOLYBDENUM DISULFIDE COMPONENT coatings on metals are so adherentthat they are not easily washed away and can provide long termlubrication even in a liquid surrounding. Molybdenum disulfide is stablein the normal atmosphere or in the absence of' oxygen over a widertemperature range than liquid lubricants, and is unaffected by extremepressures both high and low. The lubricating action of dry molybdenumdisulfide appears to be unafiected by temperatures from -40 to 700 F.Above 700 F. oxidation occurs in air, but under non-oxidizing conditionsno change in structure occurs even after heating to 2350 F.

A preferred form of molybdenum disulfide which is used in this inventionhas a particle size range of from 0.1 to 500 microns. It should beunderstood, however,

that other particle sizes may be used.

THE PAPER COMPONENT The paper used to form the lubricating discs of theinvention may be selected from any number of wellknown cellulosic fibricmaterials.

Either mechanical or chemical pulps may be used in preparing the discs.From the standpoint of ease of preparation, chemical pulp papers arepreferred. These chemical pulp papers may be characterized as eitherbeing sulfite or sulfate [Kraft].

Of these two chemical pulps, the sulfite pulps, particularly bleachedsulfite pulp papers represent the preferred cellulosic fibric materialsfrom which the lubricating discs are prepared.

As will 'be shown in the examples, while the Kraft paper stocks may beused, thesedo not have the retentive characteristic of the bleachedsulfite stocks for purposes of retaining within the interfiberinterstices the particles of molybdenum disulfide.

For a more complete description of the papers described above, referencemay be had to the Encyclopedia of Chemical Technology, John Wiley & Son,New York, First Edition.

The disc are prepared by adding 10 to 60% by weight of the molybdenumdisulfide based on the weight of pulp to a slurry of highly beaten paperpulp. The paper pulp molybdenum disulfide mixture is then thoroughlymixed so that a uniform dispersion is obtained. The water is then drawnoff by for example the application of vacuum and a moist mat containinguniformly distributed molybdenum disulfide is produced. This moist matis pressed and dried to the appropriate specified thickness. Theresulting product is a hard, molybdenum disulfide impregnated paperboard which has high strength and is nondusting. This paper board cansubsequently be brought to the proper diameter disc size. It isunderstood any conventional papermaking techniques can be used toprepare the discs.

To illustrate the preparation of'the discs, the following are presentedby way of example.

EXAMPLES Example I A sample of a bleached, sulfite paper pulp was beatenin a laboratory blender until a freeness 50 seconds was obtained. Thispaper pulp consisted of 70% cellulose and 30% water. This paper pulp wasosterized to break it up further and additional water was added to makea slurry consisting of 33%% by weight of paper pulp and 66 /s% by weightof water. About 30% by weight of molybdenum disulfide based on weight ofpulp was added to the slurry andfurther osterized for a few minutes toniix it up. This molybdenum disulfide had a particle size of about 50microns. The mixture was then put into a Buchner funnel to draw oif thewater. The molybdenum disulfide stayed in the paper. The slurry, whichwas'now a moist mat, was then pressed and dried. The resultingproduct'was a hard moly-impregnated'paper board which was high strengthand is non-dusting.

The efiluent water from the Buchner funnel had no molybdenum disulfidein it. This showed that the molybdenum disulfide was being retained bythe paper. This example is the preferred technique of making thelubricant disc.

disc on the center plate, all of the center plates were inspected. Thevisual observations are listed in Table II.

TABLE II.CENTER PLATE LUBRIOATING DISC INVESTIGATION FINDINGS Disc DiscMolybdenum disulfide replaced replaced composition of paper alter 1after 5 matrix disc month if months if- Condition observed after 1 yearTest No.:

1 30% moly (203 oz. moly)- Lubrication satisfactory-one old gall. 2.. doSame as test No.1. 3.- do N 0 fresh galls-no evidence of disclubrication good. 4. 20% moly (1.20 oz. moly) Contact areas wellpolishedsatislactory lubrication. 5.- moly (0.53 oz. moly)- Alter debrisremoved, Well lubricated. 6 .Jlo No Gal ssome cxtrusionlubricationExample 11 All the steps of Example I were followed except the paperstock was a bleachedKraft stock.

The efiluent Water from the Buchner funnel contained quantities ofmolybdenum disulfide. The paper pulp retained about one half of themolybdenum disulfide added. If this process was used to make thismolybdenum disulfide paper disc, this water would have to berecirculated in order to recover the molybdenum disulfide. Therefore,although the Kraft paper pulp may be used, the sulfite paper pulp ispreferred.

Example III A slurry of pulp comprising molybdenum disulfide wasprepared as set forth in Example 1. After the pulp and molybdenumdisulfide in it. This showed that the molybplaced into a special papermaking tray which was circular in shape and 14" in diameter. Verticallypositioned in the center of the tray was the hollow 3" diameter tube.

The pulp containing molybdenum disulfide was put into this special trayand allowed to drain until a wet mat was formed. This mat was thenpressed, squeezed and dried in conventional laboratory paper makingapparatus.

The finished molybdenum disulfide impregnated paper disc, as well asother similar paper discs were used in the tests more fully describedhereinafter.

Example IV The same procedure as Example III was used except that theamount of molybdenum disulfide used was varied. The finished discscontained 10 to by weight of molybdenum disulfide respectively.

Example V In order to test the lubricating ability of the paper discsimpregnated with molybdenum disulfide, the completed discs were placedbetween the faces of a center plate assembly of freight cars. The carswere then used in normal railroad service. The discs tested contained10%, 20% and by weight of molybdenum disulfide.

After one month, one of the paper discs containing 30% molybdenumdisulfide, was replaced. After five months, all of the paper discs werereplaced. After replacing the discs, the center plate faces were againplaced in contact.

CONCLUSIONS All of the center plates were satisfactorily lubricated.There were no fresh galls. The original galls were somewhat healed.

The results in Table II show that the amount of molybdenum disulfiderequired for satisfactory lubrication is appreciably less than 2 ounces.The paper matrix disc were very satisfactory, giving equal distributionof molybdenum disulfide and supplying sufiicient sliding action forproper lubrication. The effects of the molybdenum disulfide areaccumulative. The lubrication is better after three applications thantwo or a single application.

What is claimed is: I

1. In a railway truck, means for lubricating the truck center platescomprising a disc of paper having the approximate dimensions of saidcenter plates and having uniformly distributed there throughout from 10to 60% by weight of finely divided molybdenum disulfide.

2. The device of claim 1 where the paper disc is a sulfite paper disc.

3. The device of claim 1 where the paper disc is from 0.001 to 0.5 inthickness and contains from 20 to 40% by weight of molybdenum disulfide.

4. The device of claim 1 where the molybdenum disulfide has an averageparticle size range of from 0.1 to 500 microns.

5. The device of claim 2 where the paper disc is a bleached sulfitepaper disc.

References Cited UNITED STATES PATENTS 1,235,475 7/1917 Hickman 184-1X2,219,054 10/1940 Palm et a1. 308-L(UX) 3,000,846 9/1961 rRunton et al252-12.6X 3,127,346 3/1964 Oliver et a1. 184-1X 2,514,034 7/1950 Dean-199 2,960,352 11/1960 Wood 308-137X 3,170,740 2/1965 Smith 308-1373,466,102 9/1969 Goodwyn 308-137 FOREIGN PATENTS 622,742 6/1961 Canada308-L(UX) MANUEL A. ANTONAKAS, Primary Examiner US. Cl. X. R.

2 3 3 UNITED STATES PATENT OFFICE CERTIFICATE 01* CORRECTION Patent No.3, 5M9, 217 Dated December 22, lqjO 1nventor(s) William R. Watson It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 6, before line 1, insert After one year from the original placingof the paper Signed and sealed this 23rd day of March 1 971 (SEAL)Attest:

EDWARD M.F'LETGHER,JR. WILLIAM E. SCHUYLER, J Attesting OfficerCommissioner of Patent:

